In delivering blood to a patient intravenously, the blood type of the patient is first carefully checked against the blood type as marked on the blood container, and only then is the blood delivered to the patient. This method of matching the blood type of the patient to that of the blood donor is generally quite effective. Nonetheless, mismatches can be and have been made in using this approach, and such mistakes are most often fatal to the patient. There is therefore a need for an approach which will further reduce mistakes in blood-type matching.
While no reliable safety methods are known for prevent blood-type mismatches generally, various approaches have been tried previously which are aimed at increasing the safety of the process of plasmapheresis. Plasmapheresis is a method of obtaining plasma from a blood donor by extracting blood, centrifuging the blood to remove plasma, and then returning red blood cells to the donor. The mistake to be guarded against in plasmapheresis is that the blood cells would be returned to the wrong donor. U.S. Pat. No. 3,623,212 to Rosenberg discloses a method for avoiding such mistakes in plasmapheresis. Rosenberg employs a mating plug and a receptacle of like shape for connection between the blood bag and its support. Rosenberg's method is well suited for preventing mistakes in plasmapheresis, which typically takes place in a single centralized location. However, blood transfusions are typically given throughout a hospital, and use of Rosenberg's method to prevent blood-type mismatches in transfusions would require that each blood bag support stand throughout a hospital be equipped with a large configuration-coded receptacle, while multiple matching mating plugs would likewise have to be distributed throughout the hospital. Such an approach would be cumbersome and expensive. Additionally, as Rosenberg himself states, his method merely makes mismatches inconvenient, but would not render them impossible. A method is thus needed which cannot be circumvented by well-intentioned personnel who might simply be in a hurry to accomplish their task. U.S. Pat. No. 4,678,458 to Fredeking discloses what may be a more foolproof method of preventing a donor mismatch in plasmapheresis. Fredeking utilizes a key, unique to the donor, which is attached to the blood collector bag prior to centrifuging the blood. After the centrifuging operation, flow between the collection bag and the donor can only be established by utilizing the key in the correct lock. Again, however, this method is best suited for a centralized process such as plasmapheresis, and would be inconvenient to implement on a hospital-wide basis for preventing similar problems with blood transfusions.
U.S. Pat. No. 3,831,625 to Roediger, and U.S. Pat. No. 4,256,132 to Gunter both utilize latches having labels thereon to prevent delivery of an incorrect intravenous medication to a patient. However, both the Roediger and Gunter methods require that the labels be read and correctly followed in order to achieve their intended results, which invites human error. U.S. Pat. No. 4,795,429 to Feldstein also deals with controlling intravenous medications generally. Feldstein uses a variety of visual aids to indicate to personnel which medication is being delivered to the patient, including labels, staggered positioning, and color-coding. However, this approach is also subject to misreading by personnel. U.S. Pat. No. 4,150,673 to Watt discloses a configuration-coded entry system for a blood bag. However, Watt's method is directed toward inlets to the blood bag for receiving additives thereto. Presumably, it is because Watt is concerned with additives to the blood bag that he utilizes a multiple-inlet approach. For example, having five configuration-coded inlets as shown in Watt's drawings would serve to limit the number of potential additives to five, each of which would necessarily come from a source having a matching configuration-coded outlet. However, Watt's approach would be uniquely unsuited for preventing blood-type mismatches, as only one configuration coded outlet from a blood bag could be utilized to effectuate such a purpose. The use of more than one configuration-coded outlet on a blood bag would effectively defeat the purpose of such a system for preventing blood-type mismatching.
Therefore, it is a principal object of the present invention to provide a method and apparatus for reducing the chance of mismatching the blood-type of a patient with the type of blood to be delivered to the patient.
Another object of the present invention is to provide a method and apparatus for preventing blood-type mismatches which may be easily implemented with little change to existing equipment or procedures.